1. Field of the Invention
The present invention relates to a step-down switching regulator.
2. Description of the Related Art
Step-down switching regulators are mounted on electronic apparatuses such as TVs, personal computers, etc. The switching regulator steps down the input power supply voltage, and supplies the voltage thus stepped down to other circuit blocks mounted on the electronic apparatus.
The step-down switching regulator includes a switching transistor, a rectifying device, an inductor, an output capacitor, and a control circuit which controls the ON/OFF operation of the switching transistor.    [Patent Document 1]    Japanese Patent Application Laid Open No. 2000-345365
1. The current which is to be supplied to a load is supplied via a switching transistor. Accordingly, an increase in the load leads to a problem, in that the switching transistor generates heat, which has a local or a widespread effect. In general, by increasing the switching frequency, the properties of the switching regulator such as the load response and so forth can be improved. However, in a case in which the heat generation by the switching transistor becomes a problem, there is a need to lower the switching frequency in the circuit design. This leads to limitations on the design of the switching regulator and the circuit set. Such a problem can also occur in step-up switching regulators.
2. The step-down switching regulator includes a switching transistor, a rectifying device, an inductor, an output capacitor, and a control circuit which controls the ON/OFF operation of the switching transistor. It is convenient that the circuit operation can be modified by modifying the topology of the circuit elements which are each provided in the form of an external component, such as a switching transistor, rectifying device, while using the same control circuit.